1. Field of the Invention
The present invention relates, in particular, to an imaging lens employed in an image pickup instrument such as a compact electronic still camera or the like. More specifically, the present invention relates to an imaging lens which can also match an imaging device having a large number of pixels such as CCD.
2. Description of the Prior Art
In recent years, electronic still cameras with which pictures are easier to take and view than with conventional cameras using silver halide films have rapidly been coming into widespread use.
There have been strong demands for imaging lenses used in this kind of electronic still cameras to be of a high resolution, high performances, a small size, and a low cost. In addition, in the electronic still camera using a CCD imaging device, the imaging lens is required to be telecentric.
As an imaging lens satisfying such a requirement, a two-group, five-element configuration disclosed in Japanese Unexamined Patent Publication No. 10-20188 has been known.
Meanwhile, the recent development of CCD imaging devices is so remarkable that those having 1.5 million pixels have lately come into practice use. Hence, it has been demanded that such a CCD imaging device having a large number of pixels should be mounted to an electronic still camera, so as to yield images with a higher resolution.
When the prior art disclosed in the above-mentioned publication is employed in an instrument with a CCD having such a large number of pixels, its chromatic aberration in magnification would increase in particular, so that inconsistencies in color may occur on a reproduced picture.